UNIT XI – ANIMAL PHYSIOLOGY I

• Circulation, Respiration, Excretion, Immunity, & Hormones

• Big Campbell – Ch 42, 43, 44, 45• Baby Campbell –

Ch 22, 23, 24, 25, 26

I. CIRCULATORY SYSTEM - EVOLUTION• Gastrovascular Cavity

– Cnidarians, flatworms• Open Circulatory System

– Hemolymph– Sinuses

• Closed Circulatory System

I. CIRCULATORY SYSTEM - EVOLUTION, cont

• Components of Closed Circulatory System –

–

–

I. CIRCULATORY SYSTEM - EVOLUTION, cont• Fish: 2-chambered heart; single circuit of blood flow• Amphibians: 2 → 3-chambered heart; 2 circuits of blood flow- pulmocutaneous

(lungs and skin); systemic (some mixing)• Reptiles: Most have 3-chambered heart; crocs, gators have 4 chambers • Birds & Mammals: 4-chambered heart; double circulation = complete separation

between oxygen-rich and oxygen poor blood

II. HUMAN CIRCULATORY SYSTEM

II. HUMAN CIRCULATORY SYSTEM – The Heart

Aorta – ascending, descendingAortic valveAtrium – right, leftBicuspid (mitral) valveChordae tendinaePapillary musclesMyocardiumPulmonary arteryPulmonary valvePulmonary veinTricuspid valveVena cava – superior, inferiorVentricle – right, left

II. HUMAN CIRCULATORY SYSTEM – The Heart, cont

• Cardiac Cycle: Sequence of filling and pumping Systole- contraction Diastole- relaxation

• Cardiac Output: Volume of blood per minute. Depends on Heart rate- number of

beats per minute Stroke volume- amount of

blood pumped with each contraction

• Pulse: Rhythmic stretching of arteries by heart contraction

II. HUMAN CIRCULATORY SYSTEM – The Heartbeat• Sinoatrial (SA) node (“pacemaker”): sets rate and timing of cardiac

contraction by generating electrical signals• Atrioventricular (AV) node: relay point (0.1 second delay) spreading

impulse to walls of ventricles• Electrocardiogram (ECG or EKG)

II. HUMAN CIRCULATORY SYSTEM – The Vessels• Arteries

Carry blood away from heart

Composed of thick connective tissue, thick smooth muscle, endothelium and basement membrane

• Veins Carry blood from body to

heart Composed of thin

connective tissue, thin smooth muscle, endothelium and basement membrane

• Capillaries Site of nutrient/waste

exchange Very thin walls of

endothelium & basement membrane

Sphincters to regulate flow

II. HUMAN CIRCULATORY SYSTEM – The Vessels, cont

• Blood Pressure

– Systolic Pressure

– Diastolic Pressure

– Normal BP Ranges• Systolic → 100-140 mm Hg• Diastolic → 60-90 mm Hg

II. HUMAN CIRCULATORY SYSTEM – “Clean-Up Crew”• Lymphatic System

– “Clean-up Crew” for the circulatory system

– Returns fluid, proteins that have “leaked” out of capillaries to blood

– Vessels– Lymph

• Colorless fluid, derived from interstitial fluid

– Lymph nodes • Contain WBCs; filter

lymph, help attack viruses and bacteria

– Body defense / immunity

II. HUMAN CIRCULATORY SYSTEM – The Blood

II. HUMAN CIRCULATORY SYSTEM – Blood Types

II. HUMAN CIRCULATORY SYSTEM – The Clotting Process

II. HUMAN CIRCULATORY SYSTEM Cardiovascular Disease

• Causes >50% of all deaths in US

• Heart Attack

• Stroke

• Atherosclerosis

• Arteriosclerosis

• Hypertension

• HDLs/LDLs

III. RESPIRATORY SYSTEM• Aquatic

– gills – ventilation– countercurrent exchange

III. RESPIRATORY SYSTEM, cont• Terrestrial

– tracheal systems – lungs

IV. HUMAN RESPIRATORY SYSTEM

IV. HUMAN RESPIRATORY SYSTEM - Breathing• Negative pressure breathing

Inhalation - diaphragm contraction Exhalation - diaphragm relaxation

• Tidal volume - amount of air inhaled and exhaled with each breath (~ 500ml)• Vital capacity - maximum tidal volume during forced breathing (~ 4L)• Breathing control centers of brain are pons, medulla oblongata

Primarily a response to

IV. HUMAN RESPIRATORY SYSTEM - Circulation & Respiration

V. EXCRETION

• Nitrogenous wastes from metabolism are toxic

• Deamination

• May be excreted in one of three forms: Ammonia

Too toxic to be stored in body but diffuses well in water

Most aquatic animals Uric acid

Fairly nontoxic. Insoluble in water; eliminated as

a semi-solid paste. Seen in birds, insects, reptiles.

Urea Highly soluble in water so can be

stored in a concentrated solution.

Seen in mammals, most amphibians, sharks, bony fish

V. EXCRETION - Excretory Systems• Protonephridia ~ flatworms (“flame-bulb” systems)• Metanephridia ~ annelids (ciliated funnel system)• Malpighian tubules ~ insects (tubes in digestive tract)• Kidney ~ vertebrates

VI. EXCRETION – HUMAN URINARY SYSTEM

VI. EXCRETION – HUMAN URINARY SYSTEM, cont

• “Dirty” blood carried away from heart via descending aorta → renal artery → kidney → “clean” blood returns to heart via renal vein

• “Wastewater from blood washing exits kidney via ureter → urinary bladder → urethra

• Kidney has two main regions: Renal cortex (outer region) Renal medulla (inner region)

• Functional unit of kidney = nephron• Urine formation is a 4-part process:

Filtration Reabsorption Secretion Excretion

VI. EXCRETION – HUMAN URINARY SYSTEM, contInside a Nephron

• Afferent arteriole carries blood from renal artery into glomerulus of nephron

• Glomerulus: ball of capillaries• Filtration – small molecules

forced out of glomerulus into Bowman’s capsule

• Filtrate moves from Bowman’s capsule into renal tubule – surrounded by peritubular capillaries

• Proximal tubule: Reabsorption of nutrients Reabsorption of NaCl Reabsorption of HCO3

-

Secretion of H+

VI. EXCRETION – HUMAN URINARY SYSTEM, contInside a Nephron

• Loop of Henle:Water, NaCl reabsorptionPost-turn Loop of Henle is impermeable to waterNaCl continues to leave tubuleRequired to maintain solute concentration gradient in medulla

•Distal tubule - Refining of filtrate

•Collecting duct Reabsorbs water, NaCl, some ureaCarries filtrate to renal pelvis

•Filtrate from million + nephrons drains from renal pelvis into ureter

VI. EXCRETION – HUMAN URINARY SYSTEM, contRegulation of Kidney Function

VII. IMMUNE SYSTEM – Lines of Defense

VII. IMMUNE SYSTEM - Innate Immunity

• Barrier Defenses Skin

Secretions

Mucus

Ciliated Epithelial Cells

Lyzozyme

pH

VII. IMMUNE SYSTEMInnate Immunity – Cellular Defenses

Phagocytic Cells Neutrophils

• 60-70% of WBCs• Engulf & destroy microbes in infected tissue

Monocytes• 5% WBCs• Develop into macrophages• Large phagocytic cells that patrol interstitial fluid

Eosinophils• 1.5% WBCs• Destroy large parasitic invaders

Dendritic Cells• Found in tissues that are in contact with environment

Natural Killer (NK) Cells• Lymphocytes • Recognize lack of Class I MHC molecules – found in all normal cells; missing in virus-infected,

cancer cells• Trigger apoptosis by releasing perforins, other proteins

VII. IMMUNE SYSTEMInnate Immunity – Proteins & Inflammatory Response

• Interferon Proteins released by virus-infected cells Diffuse to healthy cells; stimulates production of proteins that inhibit viral replication

• Complement System Proteins that circulate in inactive form Activated by presence of pathogens; may lead to lysis of pathogen, activation of inflammatory response

• Inflammatory Response

VII. IMMUNE SYSTEM - Acquired Immunity• Lymphocyctes

B Cells (bone marrow) T Cells (thymus)

• Receptor proteins Plasma membrane receptors on

B and T cells Every receptor (~100,000) on a

single cell is identical Binds to a specific foreign

molecule• Antigen

Foreign molecule that elicits a response by lymphocytes (virus, bacteria, fungus, protozoa, parasitic worms, foreign cells)

• Antibodies Antigen-binding immunoglobulin Produced by B cells

VII. IMMUNE SYSTEMAcquired Immunity - Antibody Structure & Function

• Epitope - Region on antigen surface recognized by antibodies• Antibodies are composed of 2 heavy chains and 2 light chains joined by disulfide bridges• C = constant region; V = variable region, antigen-binding site • 5 classes of antibodies – IgG is most abundant

VII. IMMUNE SYSTEMInnate Immunity – Antibody Function

VII. IMMUNE SYSTEMAcquired Immunity - Types of Immune Responses

• Humoral immunity B cell activation Production of

antibodies Defend against

bacteria, toxins, and viruses free in the lymph and blood plasma

VII. IMMUNE SYSTEMAcquired Immunity - Types of Immune Responses

• Cell-mediated immunity T cell activation Cytotoxic Binds to and/or

lyses cells Defend against

cells infected with bacteria, viruses, fungi, protozoa, and parasites; nonself interaction

VII. IMMUNE SYSTEMAcquired Immunity - Helper T Lymphocytes

• Function in both humoral & cell-mediated immunity• Stimulated by antigen presenting cells (APCs)• Helper T cell replicates into a clone of activated helper T cells & memory helper T cells• Activated helper T cell produces cytokines

Stimulate activation of B cells and cytotoxic T cells Three main types of APCs are dendritic cells, macrophages, B cells

VII. IMMUNE SYSTEMAcquired Immunity – Clonal Selection

• Binding of antigen to receptor molecule activates particular lymphocyte• Response is amplified by rapid division of B, T cells; known as clonal selection• Effector cells are short-lived plasma cells that combat the antigen

Primary Immune Response

• Memory cells are long-lived cells that bear receptors for the antigen Secondary Immune Response

VII. IMMUNE SYSTEMImmunity in Health & Disease

• Acquired Immunity Conferred immunity by recovering

from disease Immunization produces an

immune response

• Passive Immunity Transfer of immunity from one

individual to another Natural – Mother to fetus;

lactation Artificial – Rabies antibodies

• ABO blood groups

• Rh factor

VIII. ENDOCRINE SYSTEM• Hormone ~ chemical signal secreted

into body fluids (blood) communicating regulatory messages

• Target cells ~ body cells that respond to hormones

• Glands may be Endocrine

Exocrine

• Hypothalamus

• Neurosecretory cells ~ nerve cells that secrete hormones

• Feedback mechanisms Negative

Positive

• Two major modes of action . . .

VIII. ENDOCRINE SYSTEM - Water-Soluble Hormones

• Include peptides, proteins, and amines

• Most common • Signaling involves three

key events: Reception

Signal Transduction

Response

VIII. ENDOCRINE SYSTEM - Steroids• Derived from cholesterol• Include sex hormones• Small, nonpolar hormones

that diffuse through cell membrane

• Mechanism of action Binds to a receptor

protein in the cytoplasm/nucleus

Hormone/receptor complex attaches to DNA

Stimulates transcription

VIII. ENDOCRINE SYSTEM

VIII. ENDOCRINE SYSTEM – GlandsPituitary Gland

• Anterior pituitary: Growth Hormone

GigantismDwarfism/acromegaly

Prolactin

FSH and LH

Thyroid Stimulating Hormone (TSH)

Adenocorticotropic Hormone (ACTH)

VIII. ENDOCRINE SYSTEM – Glands, contPituitary Gland

• Posterior Pituitary Oxytocin

Antidiuretic Hormone (ADH)

VIII. ENDOCRINE SYSTEM – Glands, cont

• Pineal Gland Melatonin

• Thyroid Gland Calcitonin

Thyroxine

• Parathyroid Gland: PTH

VIII. ENDOCRINE SYSTEM – Glands, contPituitary Gland

Pancreas• Islets of Langerhans

produce Alpha cells: glucagon~

raises blood glucose levels

Beta cells: insulin~ lowers blood glucose levels

• Type I Diabetes mellitus Insulin-dependent Autoimmune disorder

• Type II Diabetes mellitus (insipidus) Non-insulin-dependent Reduced responsiveness

in insulin targets)

VIII. ENDOCRINE SYSTEM – Glands, contAdrenal Gland

• Adrenal medulla (catecholamines): epinephrine & norepinephrine~ increase basal metabolic rate (blood glucose and pressure)

• Adrenal cortex (corticosteroids): glucocorticoids (cortisol)~ raise blood glucose mineralocorticoids (aldosterone)~ reabsorption of Na+ and K+